HELP - Yamaha R1, new fuel tank now won't start

[AndyS]

Helped a mate replace a tank on an R1 yesterday, switched all the fittings over after draining the tank, reconnected the wiring, fuel ine and vaccuum lines and refilled with fuel. But now she will turn over but won't start.
Have checked and rechecked the wiring connections, vaccuum hoses and fuel line, all to no avail.

Battery was fully charged (so it can't be cranking issue), no fuses blown.

Does any one have any ideas as to what might have happened or is there a 'trick' that I am unaware of.
Also, the fuel pump discharges fuel from the connector when the tank is upside down, so fuel is obviously getting to the line, but perhaps the fuel system is pressure based and without the correct pressure, it won't fire ?

Any help would be much appreciated.

[mac69]

open fuel cap and try it , to see if the cap is causing an air lock ,or try disconnecting the fuel line at the carb or throttle bodies and prime the pump ,it only takes a second or 2 on the button ,may just be air lock in the pump

[Halo_2]

What year and are all connections correct ??

[Mattis]

Is fuel getting to the injectors or carbs (depending on model)?

Fuel tap turned on? Blocked filter from sediment in the new tank?

[darkfibre]

It it an Injected model? If it is there should be a high pressure fuel pump. A quick google shows early models external to the tank and later pumps inside the tank. Was the tank second hand, and is the pump internal?

[AndyS]

All sorted now, thanks guys.
To answer the questions thought, it's an internal fuel pump, fuel injected model.
The connections were all correct and there was no air lock in the lines or at the throttle bodies.

Turned out that in the process of switching the pump to a brand new tank, the pump decided to give up.
It was still working, but with insufficient pressure to fully charge the system.

Once replaced everything was back to normal.